Battery Pack Conductors

[cuervo]

This isn't necessarily flashlight related, but can be....

I might feel ambitious and replace the Ni-Cd batteries in an 18V battery pack. The batteries stand vertically in a single horizontal plane, and are wired in series, 15 in all.

I was trying to think of a good way to connect the batteries. Even if I bought tabbed cells, I would have to run connectors between them. I thought of wire, but that seems a little bulky.

They old ones are connected by flat metal conductors, but I haven't been able to find anything that seems like it would work well. Any sheets of metal that I find would have to be cut. Same for any strips, but at least they would need to be cut only once to length.

I could desolder all the old ones, but was hoping to avoid having to do twice the work (desolder then resolder them to the new cells) and could possibly warp or damage them in the process.

Any ideas of something that could work?

 

[hellokitty[hk]]

I've used aluminum foil in one pack; I ended up just taping them on since it didn't need to be very sturdy.
Another one I made I just used multi-stranded copper wire.

 

[Microa]

Do you think desoldering braid can help? It is copper, flexible and flat.

 

[cuervo]

Well, I had something good and screwed it up.

I bought batteries with tabs, figuring I'd just use the tabs for the conductors between batteries. Since the batteries are wired in series in a pattern that folds back on itself, I could only use one tab off each battery. (The other tab would not be facing the correct battery. Leaving it folded down would put too much of a gap between the cells.) So, I cut the tabs off each negative terminal, figuring the positive terminal's tab would work. Well, now I'm trying to solder each positive tab directly to each negative battery end, and am running into what I hoped to avoid--a big heat sink.

I should have left the negative tabs on and folded them backwards and soldered the positive tabs to the negative tabs. I think they would have just reached and I could have clamped them together to hold until the solder cools.

I'm thinking of trying to use a microtorch to quickly heat the negative side to make a good solder connection without heating the whole battery.

 

[Microa]

The battery pack factories make them like this. Spot wield the tabs to the batteries first and then fold them straight.